How do you preserve a fish in a bottle?
Put preservatives in the bottle with the fish. Or freeze it.
Sugar is used to preserve fruits as jam/jelly. Salt is used to preserve foods such as fish and meats like bacon. Vinegar is used to preserve many different foods such as onions, cabbage, beetroot etc. Other methods of preserving include drying and smoking but these are not specifically answering your question. Examples are mushrooms and meats.